Jose Mourinho has issued the strongest indication yet that he will be in charge of Chelsea next season by revealing his plans for the first-team squad.

Mourinho says he will not require a bigger squad for the next campaign despite player fatigue and injuries being widely blamed for Chelsea's failure to win the Champions League or retain the Premiership title. Their 2007-08 squad also looks likely to include Arjen Robben.

The Dutch winger's future has been the subject of continuing speculation but a source close to the player last night confirmed that he has opened talks on a new Chelsea contract. Barcelona and Bayern Munich have been monitoring Robben's situation but it is understood the 23-year-old wants to stay at Stamford Bridge.

Mourinho, whose team face Manchester United tonight, has forged a close-knit spirit within a compact squad during his three years at Chelsea and, although events have sometimes undermined that strategy this season, there will be no significant change of approach.

"It is impossible to have a squad of 35 players," said Mourinho. "What we have to do is pray a lot because the situation we have in terms of injuries is not possible to be repeated. We had, I think, seven surgeries and 14 players with traumatic injuries, not muscular or tendon strains, everything we had was a broken bone, a knee ligament, a skull fracture, everything was really bad stuff and we cannot have a bigger squad.

"Maybe next season I have big, big problems to choose a team because I have 24 players ready to play and everybody is fit. It is something we cannot control and I think the numbers we had this season were correct."

Chelsea's main problems came over Christmas and new year when John Terry and Petr Cech were out and Mourinho was frustrated in attempts to bring in defensive cover. He believes that one extra central defender will be sufficient.

Mourinho is also aware of the potential impact that the African Cup of Nations next year might have on his squad with Didier Drogba, Salomon Kalou, Mikel John Obi, Michael Essien and Geremi all potentially involved.

"The competition is between January 20 and February 10, so it is around 20 days long," said Mourinho. "By the rules the players have to go eight to 10 days before that, so it is around a month. That's one month when there are some Carling Cup and FA Cup games, so I don't think it is a period with seven Premiership matches. I think it will be three, maximum four league games. We have to look at it like a moment when the players are injured and we cannot use them."

Something that Mourinho would like to strengthen is the quality of young players to complement his senior squad. After a successful loan spell at Plymouth earlier in the season the 18-year-old forward Scott Sinclair featured in Sunday's 1-1 draw against Arsenal. Mourinho is also set to strengthen his squad with the signing of Reading midfielder Steve Sidwell.

"What we can have, to give a little protection, is a reserve team with kids with potential and who are ready, like for example Scott Sinclair," he said.

"It is not an easy game to come on and play for 15 minutes but I think Scott is improving and we need three or four kids of 18 to 19 who are ready to play for us if we need."